S&F Ref: 878171 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Honda Motor Co., Ltd., of 1-1, Minami-Aoyama 2 of Applicant: chome, Minato-ku, Tokyo, 107-8556, Japan Actual Inventor(s): Yoshiya Omuro Kenichi Machida Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Fuel injection control device The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(1 511803_1) 1 FUEL INJECTION CONTROL DEVICE Technical Field The present invention relates to a fuel injection control device, and more 5 particularly to a fuel injection control device which can execute the correction of a fuel injection amount continuously in response to a change of throttle opening. Background Art Conventionally, there has been known a fuel injection control device which to detects a change of throttle opening and executes the correction of a fuel injection amount based on a change amount of the throttle opening. Patent document JP-B-62-9740 discloses a fuel injection control device which executes, when an increase rate of throttle opening within a predetermined time exceeds a scheduled value, the correction of an increasing amount by additional injection is independent from usual basic fuel injection. However, in patent document JP-B-62-9740, the additional injection is performed only once at an initial stage of acceleration and hence, even when a change of throttle opening is further continued, the fuel injection control device is not configured to execute the injection amount correction corresponding to such a change. To increase the 20 responsiveness of an engine output in response to a throttle operation, it is desirable to continuously execute the injection amount correction which more finely responds to the change of throttle opening. Accordingly, there exists a need to provide a fuel injection control device which can overcome the above-mentioned drawback of the related art and can execute the 25 correction of a fuel injection amount continuously in response to a change of throttle opening.
2 Summary According to a first aspect of the present invention, there is provided a fuel injection control device which executes correction of an injection amount based on throttle opening, 5 the fuel injection control device includes a basic-injection map for deriving a basic injection amount corresponding to the throttle opening and an additional-injection map for deriving an additional injection amount corresponding to the throttle opening, one engine cycle which is divided into a predetermined number of stages includes a first calculation stage for calculating the basic injection amount and a second calculation stage 10 which succeeds the first calculation stage therein, and a first injection amount obtained by applying the throttle opening measured in the first calculation stage to the additional-injection map and a second injection amount obtained by applying the throttle opening measured in the second calculation stage to the additional-injection map are compared with each other, wherein when the second injection amount is larger than the is first injection amount, an additional injection with an amount independent from the basic injection amount is performed using a value obtained by subtracting the first injection amount from the second injection amount, and when the first injection amount is larger than the second injection amount, the basic injection amount calculated in the first calculation stage is corrected. 20 In a preferred embodiment, the second calculation stage is set in a period from a point of time that the first calculation stage elapses to a point of time that an intake valve is closed in an immediate intake stroke. In a preferred embodiment, the predetermined number of stage is set by division based on crank pulse signals including a non-toothed portion, and the non-toothed portion 25 is arranged to be positioned remotest from an overlapping top position of an intake valve 3 and an exhaust valve, and the second calculation stage is set at a position where the second calculation stage does not overlap with the non-toothed portion. In a preferred embodiment, the first calculation stage is set at a predetermined stage, and the second calculation stage is set at a stage which is changeable 5 corresponding to an engine rotational speed. In a preferred embodiment, the plurality of additional-injection maps is set corresponding to the set stage of the second calculation stage. According to an embodiment of the present invention, it is possible to execute the injection amount correction in response to the change of throttle opening for every 1o one cycle. Accordingly, even when the change of the throttle opening is sharp or even when the change of the throttle opening is continued over a plurality of cycles, it is possible to optimize the correction amount by executing the injection amount correction for every one cycle. Further, it is possible to perform not only the amount increasing correction to perform the additional injection in response to the change of throttle is opening in the opening direction but also the amount decreasing correction in response to the change of throttle opening in the closing direction and hence, the responsiveness of an engine output to the throttle operation can be increased. According to an embodiment of the present invention, the correction amount can be calculated from the point of time that the first calculation stage elapses to a point of 20 time that the immediate intake stroke is finished and the injection can be performed based on the corrected injection amount in the immediate intake stroke. According to an embodiment of the present invention, in arranging the second calculation stage before the intake stroke, it is possible to set the second calculation stage outside the non-toothed portion but within a range where the actual crank pulse is 25 detected so that the stage separation becomes distinct.
4 According to an embodiment of the present invention, it is possible to always set the second calculation stage at the optimum position corresponding to the engine rotational speed. According to an embodiment of the present invention, by selecting the 5 additional-injection map corresponding to the engine rotational speed, it is possible to derive the optimum correction amount. Brief Description of the Drawings An embodiment of the present invention will be described with reference to the 10 accompanying drawings, in which: Fig. I is a block diagram showing the constitution of a fuel injection control device according to one embodiment of the invention; Fig. 2 is a time chart showing the flow of operation of the fuel injection control device; is Fig. 3 is a flow chart (1/2) showing the flow of fuel injection amount correction control; Fig. 4 A flow chart (2/2) showing the flow of fuel injection amount correction control; and Fig. 5 An example of an additional-injection map. 20 Detailed Description of the Invention A preferred embodiment of the invention is explained in detail hereinafter in conjunction with drawings. Fig. I is a block diagram showing the constitution of a fuel injection control device 100 according to one embodiment of the 25 invention. A crankshaft 1 of an engine is provided with a pair which is constituted of a 5 crank pulser rotor 2 having a non-toothed portion 2a and a pulse generator 3, wherein the pair outputs 9 crank pulses for every one rotation of the crankshaft 1. 9 pieces of projecting portions are arranged at intervals of 30 degrees, and an angle of non-toothed portion 2a is set to 120 degree. An output signal transmitted from the pulse generator 3 5 is inputted to a phase detection part 10 of an ECU 4. The phase detection part 10 detects a phase of the crankshaft 1 based on crank pulses. A stage count allocation part 502 divides one rotation of the crankshaft in nine in response to output timings of crank pulses and allocates stage counts of "0" to "9" (360-degree stage) to respective phases of the crankshaft, and allocates, upon completion 1o of the determination of the stroke of the engine, absolute stages of "0" to "17" (720-degree stage) to respective phases of I cycle (720 degree) of the crankshaft. Further, an engine rotational speed calculation part 12 detects an engine rotational speed in response to an output signal from the phase detection part 10. The fuel injection device 6 constituted of a fuel injection valve and the like is driven in response to a control is signal from a fuel injection control part 20 arranged in the ECU 4. The fuel injection control part 20 determines a control signal transmitted to the fuel injection device 6 in response to an output signal from a basic injection amount calculation part 16 and an additional injection amount calculation part 19. The basic injection amount calculation part 16 calculates a basic injection 20 amount at the time of performing the basic injection by applying throttle opening detected by a throttle opening sensor 5 and an engine rotational speed detected by the engine rotational speed calculation part 12 to a basic-injection map 15. On the other hand, an additional injection amount calculation part 19 calculates a correction amount when a predetermined change occurs with respect to the throttle opening, for example, 25 when a throttle is suddenly opened at the time of performing sudden acceleration or the like. The correction amount includes, besides an injection amount of additional 6 injection which is performed independently from the basic injection when the throttle is changed in the opening direction, a reduction amount which is an amount to be reduced from the basic injection amount when the throttle is changed in the closing direction. The additional injection amount calculation part 19 calculates a correction 5 amount based on information supplied from a throttle opening change detection part 14, an additional-injection map determination part 17 for respective calculation stages and a group of an additional-injection maps 18. The throttle opening change detection part 14 detects a change amount of throttle opening within a predetermined time based on information from the throttle opening sensor 5. Further, an additional injection amount to calculation stage determination part 13 determines a position of the additional injection amount calculation stage for calculating the additional injection amount based on information from the engine rotational speed calculation part 12 and the stage allocation part 11. The detail of the additional injection amount calculation stage is described later. Further, the additional-injection map determination part 17 for respective calculation is stages selects one additional-injection map from the group of additional-injection maps 18 based on information from the additional injection amount calculation stage determination part 13. Fig. 2 is a time chart showing the flow of an operation of the fuel injection control device according to one embodiment of the invention. Further, Fig. 3 and Fig. 4 20 are flow charts showing the flow of a fuel injection amount correction control according to this embodiment. In the time chart shown in Fig. 2, "crank angle" in an uppermost row indicates a rotational angle of the crank from a predetermined angle. The predetermined angles of the crank angle indicate a position of compression top dead center (TDC) and a position of a valve overlapping top (OLT) of a predetermined 25 cylinder. Rows directly below the uppermost row indicate open/close timing of an intake valve and an exhaust valve of the predetermined cylinder and crank pulses 7 generated by the pulse generator 3. Further, rows below these rows indicate absolute stages (720-degree stage after the stroke determination is established) corresponding to the crank pulses and relative stages "0" to "23" which divide the non-toothed portion into four and indicate I cycle which is constituted of stages all arranged at equal intervals. 5 Further, the row of "injection amount calculation stage" indicates execution timing of a basic injection amount calculation stage which constitutes a first calculation stage and execution timing of an additional injection amount calculation stage which constitutes a second calculation stage. The timings of both calculation stages correspond to the predetermined positions of the relative stage. Further, "ON/OFF of io fuel injection valve" indicates operational timing of the fuel injection device 6 which is set such that the fuel injection device 6 continues the injection under a fixed pressure during electricity is supplied and stops the injection when electricity is not supplied. Then, "throttle opening" in the lowermost row indicates an output signal of the throttle sensor 5 mounted on the throttle operated by a rider. The output signal is set such that is the output is increased along with the increase of the throttle opening. Here, it is necessary to execute the fuel injection by the fuel injection device before the intake valve is closed so that the fuel is sucked in a combustion chamber within the same cycle. In this embodiment, the basic injection amount calculation stage (C: corresponding to each English alphabet shown in Fig. 2, this definition being also 20 applicable hereinafter) in which the basic injection amount is calculated using the basic-injection map 15 is set to be executed in 8th to 9th stages of the relative stage (hereinafter, referred to as relative stages unless otherwise specified), and the basic injection amount calculation stage is set such that the injection (F) with the basic injection amount is started from the succeeding 10th stage. Here, the injection amount 25 can be set based on a period during which electricity is continuously supplied to the fuel injection valve.
8 On the other hand, there may be a case in which a required amount of fuel is sharply increased due to the sudden acceleration or the like so that the amount increasing correction of the injection amount is desirable to cope with the sharp increase of the required amount of fuel. In such a case, there has been known a technique which s performs the additional injection independently from the basic injection amount. The fuel injection control device according to the invention is characterized in that such an additional injection amount can be adjusted corresponding to a change amount of throttle opening. Further, the amount increasing correction by the additional injection can be executed not only once at an initial stage of the acceleration but also during a period in 1o which the throttle opening is changed continuously. Further, when the throttle opening is changed in the closing direction, the additional injection may not be performed and the already-calculated basic injection amount may be corrected. Such correction of the injection amount can be realized by providing an additional injection amount calculation stage (D) for calculating the additional injection amount after the basic injection amount 15 calculation stage (C) which sets the basic injection amount. Hereinafter, in conjunction with Fig. 2 and flow charts shown in Figs. 3, 4, the manner of operation of the injection amount correction control according to the invention is explained. Here, in the following explanation, the basic injection amount calculation stage (C) may be also referred to as "FICAL" and the additional injection amount calculation stage (D) may be 20 also referred to as "TIASTG" respectively. Fig. 3, 4 are flow charts showing the flow of the injection amount correction control according to the invention. In step SI, the engine rotational speed is detected by the engine rotational speed calculation part 12, and in step S2, the throttle opening is detected by the throttle opening sensor 5. In step S3, the stage number of the additional 25 injection amount calculation stage (D) corresponding to the engine rotational speed is determined by the additional injection amount calculation stage determination part 13 9 (see Fig. 1). The additional injection amount calculation stage (D) is selected among 12th to 20th stages within a setting allowable range (E) corresponding to the engine rotational speed. For example, additional injection amount calculation stage (D) may be set such that the higher the engine rotational speed, the smaller relative stage number is 5 selected. In this embodiment, the additional injection amount calculation stage (D) in the first cycle is set to the relative stage "16". Here, in this embodiment, a position of the non-toothed portion of the crank pulser rotor 2 with respect to a phase of the crank is set remotest from a valve overlapping top (OLT) of the predetermined cylinder so that the non-toothed portion does 10 not overlap with the valve overlapping top (OLT). Further, the above-mentioned additional injection amount calculation stage setting allowable range (E) is also set at a position where the additional injection amount calculation stage setting allowable range (E) does not overlap with the non-toothed portion. In this embodiment, while FICAL (C) is set to be started from a starting point of the non-toothed portion of the crank pulse, is TIASTG (D) is set at a position which avoids the non-toothed portion. In step S4, the additional-injection map corresponding to the stage number determined in step S3 is selected from the group of additional-injection maps 18. The group of additional-injection maps 18 of this embodiment may be constituted of 9 kinds of additional-injection maps which respectively correspond to the 12th to 20th stages of 20 the relative stage, for example. The additional-injection map is, as shown in Fig. 5, a data table which defines the injection amount corresponding to the throttle opening. In step S5, it is determined whether or not the phase of the crank arrives at the basic injection amount calculation stage (C). When the determination is affirmative, the processing advances to step S6. In this embodiment, when the phase of the crank 25 arrives at the 8th or 9th stage, the processing advances to step S6. The basic injection amount calculation stage (C) is a stage for calculating a basic injection amount using the 10 basic-injection map 15 based on information such as engine rotational speed, throttle opening or a vehicle speed. However, the fuel injection control device of this embodiment is configured such that the injection amount used for correction is also calculated in the basic injection amount calculation stage (C). This processing is 5 executed in step S6. In step S6, by applying throttle opening tI measured in the basic injection amount calculation stage (C) to the additional-injection map (see Fig. 5) selected in step S4, an injection amount a is calculated as a first injection amount (A). In succeeding step S7, it is determined whether or not the phase of the crank arrives at the additional injection amount calculation stage (D). When the determination io is affirmative, the processing advances to step S8. In this embodiment, when the phase of the crank arrives at the 16th stage, the processing advances to step S8. The additional injection amount calculation stage (D) is provided for enabling the correction of an injection amount in an immediate intake stroke even when the throttle opening is changed after the basic injection amount is already calculated in the basic injection amount is calculation stage (C). As described above, the additional injection amount calculation stage (D) is set within the range from 12th to 20th stages of the relative stages. The 12th to 20th stages correspond to a period from a point of time that the basic injection amount calculation stage (C) elapses to the limit stage number which allows the execution of the fuel injection while the intake valve is opened. Here, when the 20 determination is negative in step S5 or S7, the processing returns to step S1. In step S8, by applying throttle opening t2 measured in the additional injection amount calculation stage (D) to the additional-injection map selected in step S4, an injection amount P is derived as a second injection amount (B). To explain the processing by reference to the time chart shown in Fig. 2, in this embodiment, the throttle 25 starts to be opened (G) immediately before finishing of the injection (F) with the basic injection amount which is started simultaneously with the finishing of FICAL, that is, in 11 the vicinity of the 12th stage of the relative stage and, thereafter, the throttle is continuously changed in the opening direction. The injection amount 0 derived in step S8 is a value which reflects an increase of the throttle opening. In step S9, by subtracting the injection amount a from the above-mentioned 5 injection amount P, an additional injection amount T is calculated (T=p-c). In succeeding step S10, it is determined whether or not the additional injection amount T satisfies T>0. In the example shown in Fig. 2, the throttle is driven in the opening direction due to acceleration and the relationship of pf>a is established and hence, the additional injection amount T assumes a positive value. Accordingly, the determination 10 is affirmative in step S10, and the processing advances to step S 11. In step S 11, upon finishing of the additional injection amount calculation stage (D), the additional injection is executed by applying the additional injection amount T (G), and a series of controls are finished. Due to such additional injection (G), a proper amount of fuel corresponding to an increase rate of the throttle opening is supplied and hence, it is possible to enhance is responsiveness of an engine output at the time of acceleration. Here, the additional injection may be executed only when the calculated additional injection amount T is the predetermined value or more or when the detected value by the throttle opening change detection part 14 (see Fig. 1) is the predetermined value or more. On the other hand, when the determination is negative in step S10, the 20 processing advances to step S12, and it is determined whether or not the additional injection amount T is 0. When the determination is affirmative in step S12, that is, when the additional injection amount is 0, this implied that the throttle opening is not changed during the period from FICAL to TIASTG Accordingly, it is determined that the additional injection is unnecessary and hence, the processing advances to step 13 thus 25 finishing a series of controls without executing the additional injection. Here, when the throttle opening change detection part 14 (see Fig. 1) detects that the change amount of 12 the throttle opening is 0 or the change amount is less than the predetermined value, the injection amount correction control may be immediately finished. Further, when the determination is negative in step SI2, the additional injection amount T assumes a negative value. This indicates that the throttle opening is changed 5 in the closing direction during the period from the FICAL to the TIASTG When the throttle is changed in the closing direction, there is a possibility that the basic injection amount which is already calculated in the FICAL becomes excessive with respect to an injection amount required by the engine. Accordingly, in the injection amount correction control according to this embodiment, by executing the processing after step 10 S14, the proper injection amount correction can be executed even when the throttle opening is changed in the closing direction. In step S14, it is determined whether or not the injection is being performed based on the basic injection amount. This determination is made because, depending on a state of the throttle opening or the engine rotational speed, there is a possibility that the 15 injection based on the basic injection amount is continued at a point of time that TIASTG is finished. When the determination is affirmative in step S14, the processing advances to step S15, and an injected injection amount S which is already injected out of the basic injection amount is calculated. Then, in step S16, it is determined whether or not a value obtained by adding the additional injection amount T to the basic injection amount 20 is smaller than the injected injection amount S. Here, the additional injection amount T is a negative value and hence, the determination in step S16 may be expressed as the determination "whether or not a correction amount obtained by subtracting an absolute value of the additional injection amount T from the basic injection amount is smaller than the injected injection amount S". When the determination is affirmative, it is 25 determined that the necessary amount is already injected and hence, the processing advances to step S17 and the injection is stopped. On the other hand, when the 13 determination is negative in step S16, the processing advances to step S18 and the remaining amount of fuel is injected based on the corrected amount (basic injection amount + T) which is obtained by subtracting the absolute value of the additional injection amount T from the basic injection amount, and a series of controls are finished. 5 The injection amount correction described above can be executed for every 1 cycle. As shown in Fig. 2, even when the change of the throttle opening is continued over the next cycle, an injection amount a2 is derived in the next FICAL (stage J) and P2 is derived in TIASTG which is set thereafter (stage K), and (x2 is subtracted from P2 thus calculating a new additional injection amount supplied in the next intake stroke. 10 As described above, according to the fuel injection control device of the invention, after the FICAL (first calculation stage) for calculating the basic injection amount and before the immediate intake stroke, the TIASTG (second calculation stage) for calculating the additional injection amount is provided, and the correction amount is calculated based on the throttle opening measured in each stage so as to correct the fuel 15 injection amount of the immediate intake stroke and hence, it is possible to execute the injection amount correction corresponding to the change of the throttle opening for every 1 cycle. Accordingly, even when the change of the throttle opening is continued over a plurality of cycles, the injection amount correction can be executed for every I cycle so as to optimize the correction amount and hence, it is possible to further enhance the 20 responsiveness of the engine output in response to the throttle operation. Further, a shape of the crank pulser rotor, the number of the crank pulses, the number of the absolute stages and stage numbers allocated to the relative stages, the setting positions and lengths of the FICAL and the TIASTQ the modes of the additional-injection maps, items of the flow charts of the fuel injection control shown in 25 Fig. 3, 4 and the like are not limited to the above-mentioned embodiment, and various modification are conceivable.